1. Field of the Invention
The present invention relates to a process for producing L-valine or L-lysine by fermentation. L-Valine and L-lysine are useful as essential amino acids incorporated into medicines, diets, etc. and their economical production on a commercial scale is needed.
2. Background of the Invention
Production of amino acids by the fermentation has been practiced using saccharides (carbohydrates) as the main starting materials, but it suffers from various problems such as high cost and unstable supply due to the fact that the starting materials are agricultural products, copious amounts of by-products derived from a large proportion of impurities contained in the starting material are produced, colored waste water is generated from the fermentation process, etc., and therefore fundamental improvements have been sought.
As one alternative, a process using hydrocarbons as the starting materials has been studied, but even this process has a drawback that some hydrocarbons are gaseous and some are not soluble in water, which greatly restricts their application on a commercial scale and, as a result, the yield is limited.